Justine Neville (left) and Brendan Crossman (right) work to download and examine the data obtained from the site's sap flow probes, which were installed in early May. To learn more, contact Justine Neville at jneville@usgs.gov or David Walters at davidwalters@usgs.gov.
David C Walters
David is a biological science tech with the Eastern Ecological Science Center at the Patuxent Research Refuge in Laurel, MD
David is a wetland ecologist, researching how coastal wetlands respond to sea level rise. With a background in biological and physical sciences, his work focuses on the interaction between wetland plant species and their physical environment.
Professional Experience
2020-Present - U.S. Geological Survey, Eastern Ecological Science Center, Biologist, Coastal Wetlands Group
2017-2020 - NSA Contractor with U.S. Geological Survey, Patuxent Wildlife Research Refuge, Coastal Wetlands Group
2013-2017 - Virginia Institute of Marine Science, Laboratory and Research Specialist
Education and Certifications
M.S., University of North Carolina- Chapel Hill, Geology (2013)
B.S., Longwood Univerity, Biology, concentration in Ecology (2011)
Science and Products
Minerals Resources Life Cycle Integrated Science Team
2025 Wetland Accretion Measurements from Smithsonian Environmental Research Center SMARTX Warming Plots 2025 Wetland Accretion Measurements from Smithsonian Environmental Research Center SMARTX Warming Plots
Sediment core radioisotope measurements in coastal wetlands along the Chesapeake Bay Sediment core radioisotope measurements in coastal wetlands along the Chesapeake Bay
Surface Elevation Tablet Measurements from 10 USGS Sites Along the US Atlantic Coast (2005-2020) Surface Elevation Tablet Measurements from 10 USGS Sites Along the US Atlantic Coast (2005-2020)
Environmental and Vegetation Data from Marsh-Forest Transgression Experiment at Blackwater National Wildlife Refuge, MD, USA Environmental and Vegetation Data from Marsh-Forest Transgression Experiment at Blackwater National Wildlife Refuge, MD, USA

Justine Neville (left) and Brendan Crossman (right) work to download and examine the data obtained from the site's sap flow probes, which were installed in early May. To learn more, contact Justine Neville at jneville@usgs.gov or David Walters at davidwalters@usgs.gov.

Close up of the newly installed sap flow sensors at Blackwater National Wildlife Preserve. These sensors were installed by EESC's Justine Neville and Ken Krauss of the USGS Wetland and Aquatic Research Center in Lafayette, LA. These sensors will be used to analyze how the trees in a marsh ecosystem respond to changing ecological and climatic conditions.
Close up of the newly installed sap flow sensors at Blackwater National Wildlife Preserve. These sensors were installed by EESC's Justine Neville and Ken Krauss of the USGS Wetland and Aquatic Research Center in Lafayette, LA. These sensors will be used to analyze how the trees in a marsh ecosystem respond to changing ecological and climatic conditions.
EESC USGS Mendenhall Fellow Justine Neville installing sap flow probes at Blackwater National Wildlife Refuge with USGS colleague Ken Krauss from USGS Wetland and Aquatic Research Center in Lafayette, LA. Sap flow probes will be used to monitor transpiration rates in coastal forests to assess the water usage of trees experiencing stress from inundation.
EESC USGS Mendenhall Fellow Justine Neville installing sap flow probes at Blackwater National Wildlife Refuge with USGS colleague Ken Krauss from USGS Wetland and Aquatic Research Center in Lafayette, LA. Sap flow probes will be used to monitor transpiration rates in coastal forests to assess the water usage of trees experiencing stress from inundation.
Brendan Crossman measures porewater salinity in a vegetation plot situated on a survey transect from the wetland into the adjacent upland forest.
Brendan Crossman measures porewater salinity in a vegetation plot situated on a survey transect from the wetland into the adjacent upland forest.
Effects of chronic metal exposure and metamorphosis on the microbiomes of larval and adult insects and riparian spiders through the aquatic-riparian food web Effects of chronic metal exposure and metamorphosis on the microbiomes of larval and adult insects and riparian spiders through the aquatic-riparian food web
Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling
Metal-rich lacustrine sediments from legacy mining perpetuate copper exposure to aquatic-riparian food webs Metal-rich lacustrine sediments from legacy mining perpetuate copper exposure to aquatic-riparian food webs
Continental-scale nutrient and contaminant delivery by Pacific salmon Continental-scale nutrient and contaminant delivery by Pacific salmon
Microtopographic variation as a potential early indicator of ecosystem state change and vulnerability in salt marshes Microtopographic variation as a potential early indicator of ecosystem state change and vulnerability in salt marshes
Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae
PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study
Evolutionary and ecological correlates of thiaminase in fishes Evolutionary and ecological correlates of thiaminase in fishes
A novel approach to assessing natural resource injury with Bayesian networks A novel approach to assessing natural resource injury with Bayesian networks
Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs
Identifying invertebrate indicators for streamflow duration assessments in forested headwater streams Identifying invertebrate indicators for streamflow duration assessments in forested headwater streams
Climate-driven tradeoffs between landscape connectivity and the maintenance of the coastal carbon sink Climate-driven tradeoffs between landscape connectivity and the maintenance of the coastal carbon sink
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Minerals Resources Life Cycle Integrated Science Team
2025 Wetland Accretion Measurements from Smithsonian Environmental Research Center SMARTX Warming Plots 2025 Wetland Accretion Measurements from Smithsonian Environmental Research Center SMARTX Warming Plots
Sediment core radioisotope measurements in coastal wetlands along the Chesapeake Bay Sediment core radioisotope measurements in coastal wetlands along the Chesapeake Bay
Surface Elevation Tablet Measurements from 10 USGS Sites Along the US Atlantic Coast (2005-2020) Surface Elevation Tablet Measurements from 10 USGS Sites Along the US Atlantic Coast (2005-2020)
Environmental and Vegetation Data from Marsh-Forest Transgression Experiment at Blackwater National Wildlife Refuge, MD, USA Environmental and Vegetation Data from Marsh-Forest Transgression Experiment at Blackwater National Wildlife Refuge, MD, USA

Justine Neville (left) and Brendan Crossman (right) work to download and examine the data obtained from the site's sap flow probes, which were installed in early May. To learn more, contact Justine Neville at jneville@usgs.gov or David Walters at davidwalters@usgs.gov.
Justine Neville (left) and Brendan Crossman (right) work to download and examine the data obtained from the site's sap flow probes, which were installed in early May. To learn more, contact Justine Neville at jneville@usgs.gov or David Walters at davidwalters@usgs.gov.

Close up of the newly installed sap flow sensors at Blackwater National Wildlife Preserve. These sensors were installed by EESC's Justine Neville and Ken Krauss of the USGS Wetland and Aquatic Research Center in Lafayette, LA. These sensors will be used to analyze how the trees in a marsh ecosystem respond to changing ecological and climatic conditions.
Close up of the newly installed sap flow sensors at Blackwater National Wildlife Preserve. These sensors were installed by EESC's Justine Neville and Ken Krauss of the USGS Wetland and Aquatic Research Center in Lafayette, LA. These sensors will be used to analyze how the trees in a marsh ecosystem respond to changing ecological and climatic conditions.
EESC USGS Mendenhall Fellow Justine Neville installing sap flow probes at Blackwater National Wildlife Refuge with USGS colleague Ken Krauss from USGS Wetland and Aquatic Research Center in Lafayette, LA. Sap flow probes will be used to monitor transpiration rates in coastal forests to assess the water usage of trees experiencing stress from inundation.
EESC USGS Mendenhall Fellow Justine Neville installing sap flow probes at Blackwater National Wildlife Refuge with USGS colleague Ken Krauss from USGS Wetland and Aquatic Research Center in Lafayette, LA. Sap flow probes will be used to monitor transpiration rates in coastal forests to assess the water usage of trees experiencing stress from inundation.
Brendan Crossman measures porewater salinity in a vegetation plot situated on a survey transect from the wetland into the adjacent upland forest.
Brendan Crossman measures porewater salinity in a vegetation plot situated on a survey transect from the wetland into the adjacent upland forest.
Effects of chronic metal exposure and metamorphosis on the microbiomes of larval and adult insects and riparian spiders through the aquatic-riparian food web Effects of chronic metal exposure and metamorphosis on the microbiomes of larval and adult insects and riparian spiders through the aquatic-riparian food web
Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling Ecosystem drivers of freshwater mercury bioaccumulation are context-dependent: Insights from continental-scale modeling
Metal-rich lacustrine sediments from legacy mining perpetuate copper exposure to aquatic-riparian food webs Metal-rich lacustrine sediments from legacy mining perpetuate copper exposure to aquatic-riparian food webs
Continental-scale nutrient and contaminant delivery by Pacific salmon Continental-scale nutrient and contaminant delivery by Pacific salmon
Microtopographic variation as a potential early indicator of ecosystem state change and vulnerability in salt marshes Microtopographic variation as a potential early indicator of ecosystem state change and vulnerability in salt marshes
Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae Geographic drivers of mercury entry into aquatic food webs revealed by mercury stable isotopes in dragonfly larvae
PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study
Evolutionary and ecological correlates of thiaminase in fishes Evolutionary and ecological correlates of thiaminase in fishes
A novel approach to assessing natural resource injury with Bayesian networks A novel approach to assessing natural resource injury with Bayesian networks
Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs Mercury isotope values in shoreline spiders reveal transfer of aquatic mercury sources to terrestrial food webs
Identifying invertebrate indicators for streamflow duration assessments in forested headwater streams Identifying invertebrate indicators for streamflow duration assessments in forested headwater streams
Climate-driven tradeoffs between landscape connectivity and the maintenance of the coastal carbon sink Climate-driven tradeoffs between landscape connectivity and the maintenance of the coastal carbon sink
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.